A new Solanum satellite DNA containing species-specific sequences which can be used for identification of genome parts in somatic hybrids of potato

Abstract

Complete 337-bp repeats of a satellite DNA component of Solanum demissum were cloned after PCR amplification and subsequently sequenced (pSDB6). This satellite was firstly detected by hybridization of Solanum DNA with a short clone pSDT382, which was previously cloned from S. demissum and described to be species-specific for some Solanum wild species and also for some breeding lines of potato. Within the sequence of pSDB6 high similarity of 77% was detected to a 75-bp region of a common Solanum-specific repeat (pSA287; 183 bp in length). Obviously, the species-specificity is restricted to a short region within the 337-bp element. This new element appears to be present in S. okadae, S.kurtzianum, S. maglia, S. acaule and S. demissum (belonging to different series of potato) and could be also detected by Southern blot in some S. tuberosum breeding lines. Therefore, the short clone pSDT382 can be used to detect specific genome parts of species such as S. okadae, S. kurtzianum and S. maglia in symmetric somatic hybrids obtained by protoplast fusion with selected S. tuberosum breeding lines not containing this repeat type. Evolution of satellite DNA within Solanum/Lycopersicon species is discussed.